NOVEL BINUCLEAR VANADIUM(V) SCHIFF-BASE CATIONS CONTAINING SINGLE FLUORINE BRIDGES AND THE STRUCTURE OF DIFLUORODIOXOVANADATE(1-)

The complex [VO(salen)] [H(2)salen = N,N'-ethylenebis(salicylideneimin e)] reacted with HBF4.Et(2)O in air to produce the novel linear specie s [{VO(salen)}(2)(mu-F)](+), the structure of which has been determine d as its BF4- and [VO2F2](-) salts. The perchlorate and triflate (O3SC F3-) salts have been characterised spectroscopically and analytically, as well as the tetrafluoroborate homologues from salicylaldehyde and 2-methylpropylenediamine, and from ethylenediamine and 3-methoxysalicy laldehyde. The [VO2F2](-) is mononuclear in the above salt, as well as in [PPh(4)][VO2F2]. compared to a polynuclear form found in[NH4][VO2F 2]. The mononuclear anion was also fully characterised by F-19 and V-5 1 NMR spectroscopy.